3,180 research outputs found
Weak one-basedness
We study the notion of weak one-basedness introduced in recent work of Berenstein and Vassiliev. Our main results are that this notion characterises linearity in the setting of geometric þ-rank 1 structures and that lovely pairs of weakly one-based geometric þ-rank 1 struc- tures are weakly one-based with respect to þ-independence. We also study geometries arising from infinite dimensional vector spaces over division rings
Ramsey expansions of metrically homogeneous graphs
We discuss the Ramsey property, the existence of a stationary independence
relation and the coherent extension property for partial isometries (coherent
EPPA) for all classes of metrically homogeneous graphs from Cherlin's
catalogue, which is conjectured to include all such structures. We show that,
with the exception of tree-like graphs, all metric spaces in the catalogue have
precompact Ramsey expansions (or lifts) with the expansion property. With two
exceptions we can also characterise the existence of a stationary independence
relation and the coherent EPPA.
Our results can be seen as a new contribution to Ne\v{s}et\v{r}il's
classification programme of Ramsey classes and as empirical evidence of the
recent convergence in techniques employed to establish the Ramsey property, the
expansion (or lift or ordering) property, EPPA and the existence of a
stationary independence relation. At the heart of our proof is a canonical way
of completing edge-labelled graphs to metric spaces in Cherlin's classes. The
existence of such a "completion algorithm" then allows us to apply several
strong results in the areas that imply EPPA and respectively the Ramsey
property.
The main results have numerous corollaries on the automorphism groups of the
Fra\"iss\'e limits of the classes, such as amenability, unique ergodicity,
existence of universal minimal flows, ample generics, small index property,
21-Bergman property and Serre's property (FA).Comment: 57 pages, 14 figures. Extends results of arXiv:1706.00295. Minor
revisio
Development of a readiness ruler for use with alcohol brief interventions
Background
A quick method of assessing readiness to change was needed for a major study of implementing screening and alcohol brief intervention in England. For this purpose, a Readiness Ruler that had been validated among a sample of male college students in the USA was adapted and applied to a sample of excessive drinkers in a general medical practice located in a deprived area of Gateshead, England.
Methods
72 participants identified as excessive drinkers by health professionals completed a single-item Readiness Ruler, the 12-item Readiness to Change Questionnaire (RCQ) and the AUDIT questionnaire.
Results
In terms of concurrent validity, the relationships between the Readiness Ruler, on the one hand, and either stage of change allocation or a dimensional score derived from the RCQ, on the other hand, were highly significant but weaker than expected. When patients who endorsed the “maintenance” point on the Readiness Ruler were excluded from the analysis, the above relationships were considerably strengthened for reasons that are discussed. On this basis and with another small change, a final Readiness Ruler was developed.
Conclusion
If the validity of the Readiness Ruler is confirmed in subsequent research, a quick and simple way of measuring readiness to change will be available for research or clinical work with alcohol brief interventions
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis
T Pyxidis is the only recurrent nova surrounded by knots of material ejected
in previous outbursts. Following the eruption that began on 2011 April 14.29,
we obtained seven epochs (from 4 to 383 days after eruption) of Hubble Space
Telescope narrowband Ha images of T Pyx . The flash of radiation from the nova
event had no effect on the ejecta until at least 55 days after the eruption
began. Photoionization of hydrogen located north and south of the central star
was seen 132 days after the beginning of the eruption. That hydrogen recombined
in the following 51 days, allowing us to determine a hydrogen atom density of
at least 7e5 cm^-3 - at least an order of magnitude denser than the previously
detected, unresolved [NII] knots surrounding T Pyx. Material to the northwest
and southeast was photoionized between 132 and 183 days after the eruption
began. 99 days later that hydrogen had recombined. Both then (282 days after
outburst) and 101 days later, we detected almost no trace of hydrogen emission
around T Pyx. There is a large reservoir of previously unseen, cold diffuse
hydrogen overlapping the previously detected, [NII] - emitting knots of T Pyx
ejecta. The mass of this newly detected hydrogen is probably an order of
magnitude larger than that of the [NII] knots. We also determine that there is
no significant reservoir of undetected ejecta from the outer boundaries of the
previously detected ejecta out to about twice that distance, near the plane of
the sky. The lack of distant ejecta is consistent with the Schaefer et al
(2010) scenario for T Pyx, in which the star underwent its first eruption
within five years of 1866 after many millennia of quiescence, followed by the
six observed recurrent nova eruptions since 1890. This lack of distant ejecta
is not consistent with scenarios in which T Pyx has been erupting continuously
as a recurrent nova for many centuries or millennia.Comment: 27 pages, 10 figures, submitted to the Astrophysical Journa
Addressing Tobacco Use in Adult Mental Health Service Programs
People with Severe Mental Illness (SMI) consume nearly half of all tobacco sold in the US (Lasser, Boyd, Woolhander, Himmelstein, McCormick, & Bor, 2000). Compared to the general population, individuals diagnosed with SMI are at greater risk of co-morbid health problems and premature death (Centers for Disease Control and Prevention, 2002; National Association of State Mental Health Program Directors, 2006). Often individuals with SMI are unaware of supportive services such as Quitlines, Nicotine Anonymous (NIC-A) meetings, and/ or Nicotine Replacement Therapy (NRT). To compound matters, many states have cut tobacco cessation funding, and few mental health programs provide integrated approaches to tobacco cessation. Programs lack trained staff or peers to assist people with SMI who wish to quit or to learn about the harmful consequences of tobacco use (e.g. cigarettes, cigars, or chewing tobacco). However, evidence suggests that people with SMI can be successful in quitting. This Issue Brief describes our efforts to engage this population in tobacco cessation activities
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